Process of preparing anhydrous ammonia



(No Model.)

P, J. MGMAHON. 'PROCESS OF PREBARING'ANHYDROUS AMMONIA. l No. 367,992. latented Aug. 9, 1887.

n. Pains. mmummrmr. wmxngm. uV c UNITED STATES PATENT OFFICE.

PRocEss'oF PREPARING ANHYDROUS AMMONIA.

SPECIFICATION' forming part of Letters Patent No. 367,992, dated August 9, 1887.

Application mea August 14, 18st.

To all whom it may concern,.-

Be it known that I, PATRIcII J. McMAHoN, a citizen of the United States, residing at New Orleans, in the parish of Orleans, State of Louisiana, have invented certain new and use ful Improvements in Methods of Preparing, Using, and Purifying Anhydrous and So1u-` tions of Ammonia `for Motive Power, Refrig-v erative, .and other Purposes, of which thefol?,- lowing is aspecitication, reference being had therein to the accompanying drawings.

This invention has relation to the utilization of ammoniacal gas as a motive power and as an agent inrefrigerating processes; and among the objects of my invention are to subject ordinary aqua-ammonia to such a treatment as shall produce therefrom a more, pure or strictly anhydrous ammonia for the uses specitied,and to subject to treatment the reabsorbing liquid used to receive the anhydrous ammonia after the same has been employed as a motive power in ammonia-engines and similar apparatuses,

4which treatment shall separate and restore therefrom a4 more pure or condensed anhydrous ammonia than hitherto, and during the treatment above mentioned to separate from the ammoniacal gas any air which may have within the apparatus, and, iinally, to purify the ammonia solution from any oils or other impurities with which the said solution may have become contaminated in passing through the mechanical structure employed in utilizing the ammonia as a motive power.

Further objects and advantages o'f my invention will appear in the following description, and the novel featuresA thereof will be particularly pointed out in the claims.

My invention involves, in fact, not only an apparatus adapted to perform the several operations hereinafter described, buth also certain specific portions of the apparatus which are capable of use in connection with other apparatus than that herein shown; and my invention also-involves a particular manner' or method .of treating aqua-ammonia for the purf pose specified, which mannerv or method is not necessarily the only manner or method of using the apparatus shown and described,and

' seriaiNo. 210,959.' (No model.)

therefore is something more than the mere operation of said apparatus, so that I do not limit myinventionin regard to said method to practicing the same by means of an apparatus constructed in all substantial .particulars like that herein shown and described.

Novel subject-matter herein shown and described is not claimed, as it is presented in a companion application tiled herewith.

. Referring to the drawings, Figure 1 is a plan.

Fig. 2 is a side elevation of an apparatus constructed in accordance with and adapted to the practice of my invention. Fig. 3 is a side elevation oil' the dehydrator, its coupling a being adapted to t the coupling a ot' the still,

for the purpose of supporting the dehydrator upon the still, and its pipe G8 communicates with the pipe G on the still.

Like letters refer to like parts in all the lig ures.

AS a means for vaporizing aqua-ammonia, I employ a boiler or still, A, which comprises a system of steam-pipes, A', supplied from any suitable steam-generator through a pipe, A2, at the bottom of the still. Within thestill a supply of aqua-ammonia is maintainedto submerge the steam-pipes and cover the same to about the depth indicated by the dotted lines A3 From the bottom of the retort there is a dischargepipe, A, for condensed water, andfrom the same part of the retort another pipe, A5, provided with a valve, A, extends into `an equalizer or heater, B. A pump, C, is connected with the equalizer B by a pipe, B', and by another pipe, C','(sec Fig. 1,) with the lower one of a series of two or more ammoniaetanks, D D D2, connected with each other by pipes D3, having within each tank a check-valve, D4, which, by means of suitable lever-connections D5 D and handles D7 thereon, may be opened, to allow a free passage of ammonia from one tank to another. A similar pipe, D8, and valve D, operated by a handle, D1, affords communication from the upper tank, D2, with a water-column, Dit, arranged at a point above the upper tank, so that liquid will pass from the water-column down through the several tanks in the series.

Another pipe, B, communicates with the tank F, and still another pipe, B", gives communication between the equalizer and the Vertical IOO blow-olf tank E, each of these pipes being provided with stop-cocks B7* Bli, and by means of a pipe, E', extending from the top of the blowoff tank, communication is had with the lower tank, D, of the series above mentioned, the pipe E passing in to near the bottom of said tank.

The upper part of thc still A is provided with a series of drip-shelves, A?, which are preferably quartensections of disks or quadrangular shelves arranged to overlap each other, so as to form a series of intercepting plates, in order that liquid admitted in the upper part of the retort may drip down the successive plates of the series.

B represents a pipe extending from the top of the equalizer to the top of the still, and serves to supply liquid at such a point that the same will drip from one plate A7 to another in the series shown. rlhese plates constitute what may be termed the rcctifying portion of the still.

Upon the still A, I mount a drier or dehydrator comprising a vertical column, G, from the top of which extends a pipe, G, which communicates with a column, GZ, near its bottom, which column is in turn provided with a similar pipe, G', connnunieating in a like manner with another colunm. These columns and pipes'may bc increased in number to any desired extent, and each is provided at its bottom with an outlet, G3, communicating with a connecting-pipe, G",whieh communicates with a drip-pipe, G, which is connected by means of a pipe, G, having a valve, G7, with the upper portion of the still. From the top of the last column, Gi', of the series of dehydrators there extends a pipe, G", to a condenser, comprising a coil, 1I, arranged in a vertical case, H', which is provided at its top with a tank, H", having its` bottom perforated, so that by means of a pump, 11", and pipes H5 a supply of cold water may be caused to circulate around the eoil H. From the coil a pipe, 11, extends to a tank, HT, and from this tank there extends a pipe, 11E, provided with a valve or cutolT, 11, of any ordinary construction. At the end of the pipe H8 is a coupling, 1110, the opposite member, H, ot which is secured to a pipe, 11, which communicates with the ammonia-reservoir of a motor, or it maybe with any part of a ref ri gerating apparatus intended to receive the animoniacal refrigerative agent employed.

1 is a vacuum-pump, connected by means of one pipe, 1, (see Fig. 1,) to the lower ammonia-tank, D, and by another pipe, 12, with a solution-tank, J, from which a pipe, J', cx tends toa coupling, J2, the companion element, J, of which is secured to a pipe, JW, communicating with the reabsorbing-liquid tank of a motor or refrigerating apparatus. Interiuediate the tank J and coupling J2 and the pipe J, to which said coupling is secured, is a branch pipe, J (see Fig. 1,) from which there extends a pipe, J 5, to an elevated solutiontank, Ji. The branch pipe J is provided with a valve, Ji, the pipe J with a valve, J, and the pipe J3 with a valve, J". Between the valve H and coupling Hl0 there is a small pipe, K, having a valve, K', which pipe communicates with the pump I.

The mode of operation is as follows: The still A is filled with concentrated aquaammonia, so as to submerge the tubes, and above the same, as shown by dotted lines A3. Steam is admitted through thepipe Ainto the tubes, and through them heating the concentrated solution surrounding them and evaporating the ammonia or expelling it as a gas, which rises into the drier G, and from thence passes through the dehydrators G2. The aqueous vapor, condensing, falls to the bottoms ofthe columns constituting the dehydrators, and is finally collected at the drip-pipe G5, and is conducted through the pipe and valve G GT into the reservoir, where it drips over the rectifying-plates A7 and` joins the solution in the still to be again treated. The gas then passes from the last column or dehydrator through the pipe G into thc condensing-coil H,where the heat given to it in the still is taken up by a body of water supplied by the pump 1I to the tank I1, thebottom of which isperforated to permit of the passage of water over the coils, so that the gas therein is condensed to a liquid-thatis, to a purified anhydrous ammonia-which is collected in the tank 1li, from which it is conducted by the pipe H to the pipes for use in the manner hereinafter described. rlhe feed'pump C takes a suppl y of aqua-ammonia from the tank D and keeps up the level in the still A, through the equal` izer B and feed-pipe B, from which it drips down over the rectiers AT. The ammonia being about all driven out of that portion ot" the still near the bottom, a continuous blowoff or discharge thereof' is maintained through the pipe A, equalizer B, and pipe B* into the vertical blowoff tank E, valves G* and B* being provided to control said blow-oft. \Vhen the weaker solution thus discharged arrives in the vertical blow-oft tank, it is there released from pressure, and the heat duc to the higher pressure in the still is liberated and expels any remaining gas in the solution, and this gas passes through the pipe E into the tank D, where it is absorbed, thus increasing the strength of the solution therein, as well as reducing the strength of that which is blown oil' or discharged into the tank E, which solution settles into the wcak-solution tank F, from which, by a suitable pipe, Fit, Fig. 1, it may be conducted from time to time to the weak'selution tank J", from which supplies of the saine may be furnished to a refrigerative or motor apparatus, in the manner to be now described.

To charge the carmotor or other apparatus, the couplings 11" 1'1" are connected with the ammonia receiver or generator, and the couplings Jz J are connected-with the reabsorbing or weak-solution tank, the former to be charged from the tank H7 and the latter to be charged IOO IIO

from the tank J, and both to be emptied by means'of the tank J and its connection. Before the couplings are disconnected a'vacuum is produced between theV couplings Hw H, J"

J, and similar couplings on the motor or apparatus to be supplied by opening the connections between the tank J and' the pipes communicating with the couplings. In the system of pipes communicating with the weaksolution tank of the apparatus to be supplied, the valves JYs and Jare opened and the valve J7 closed, when the solution in said tank (which, it is understood, has become more o r less saturated with gas in the operations to which it has been subjected in a use of the motor or other apparatus) is drawn into the tank J by reason of the vaccu m'maintained therein by the pumpI. Ontheotherhand,thevalveH9, which controls thesupply of the anhydrous ammonia from the tank H7 to any apparatus which is to be supplied, is closed, and the valve K in the pipe K is opened, whereby the liquid ammonia from the tank or generator of the apparatus, together with any air or other impurities which have collected therein, is also conducted into the tank J. It naturally follows that by the connections arranged as just described not only are the contents of the tank or generator removed, but also that a vacuum is produced in them and in the pipes connecting the same with the couplings'. The v-alves K' and Je are now closed, and the rValve J7 is opened to permit the entrance of a fresh supply of thevweak solution from .the tank J, and the valve H9 is opened to furnish a fresh supply or charge of anhydrous ammonia from the tank H7. `When supplied, these valves are closed and the couplings separated, and the operation of supplying has been accomplished with a removal of air from the apparatus suppliedvand a prevention of the introduction of air into the anhydrous-ammonia storage-tank and other parts of the apparatus from which it is desired to preventits introduction. The pipe K, which is used merely to produce an exhaust in the pipes between the couplingsthat is to say, to exhaust the air from the pipes which connect the motor or apparatus to be supplied with the apparatus herein shownis connected directly to' thefpump I, thereby avoiding the introduction of air alone directly into the tank J. 'lhe main supply of concentrated ammonia is put into the tanks D D' D2, and water is put into the vertical tank Didi, which is elevated above the ammonia-tanks and connected therewith, as described. Vhen a charge of concentrated solution-that-is, a quantity of water which is fully charged with ammonia-is withdrawn from a car-motor or other apparatus, it is pumped directly into the lower tank, D, and any gas withdrawn bythe vacuum-pump I may be forced through also, as well as any air received from the pipes. If the solution in the tank D be not already saturated, it will absorb this gas. Otherwise the gas will pass upwardly through the cheekvalve D4 into the tank D', and, if necessary,

into the tank D2, and the air taking the same course will pass the check DI and ih rough the water in the column D3, where it will escape into the atmosphere, while any gas which might follow the air that distance will be retained and absorbed by the water in said tank DW. This refers more particularly to the air which is in the pipes before coupling, which air must be gotten rid of.

Vhen it is desired to get additional solution in the tank D for feeding the still A, the ch eck-valve D4 is raised by means of thelevers D3 DG and handles Dl, and the required amount is run down from the tank D'. In alike manner the latter tank may be replenished from the next tank, D',above by manipulating the handle D7, and by means of the handleD10 and its connections with the check D9 the waterin the `column D3 may be introduced into the upper tank when said water has become sufieiently saturated. A new supply of water is provided in the tank D3 to take t-he placeof that removed. Y

Vhile utilizing gas in the cylinder of a motor it takes up the black oil used for lubrication (and other impurities) and carries it off in the reabsorbing solution, rendering it black and dirty. This impuritypis eliminated from time to time by taking a portion of the weak solution into the small boiler E2 and heating the same therein until all the ammonia is eX- pelled from it as a gas, a suitable connectingpipe (not shown) being provided from the tank J to the boiler E, and a pipe, E3, from theboiler to the tank D, the latter to conduct the gas separated from the impure weak solution.` After the expulsion of the ammonia the dirty residuum is withdrawn from the boiler and may be thrown away; but if any traces of ammonia still remain in it it can be utilized as a fertilizer. rlhe amount of weak solutionwithdrawn into t-he boiler E should be replaced by an amount of water in the vertical IOO IIO

tank D3, which will render the density of the Y IZO valves from the motor and from the supplyjtank, and subsequently shutting off communication of said pipes with the exhaust-pipe and opening up communication between the supply-tank and the connect-i ng-pipe,substantiall y as specified.

2. The method of removing impurities taken up by the reabsorbing liquid of a motor or other apparatus and of maintaining a uniform strength of the liquid ammonia employed in the system, which consistsin heating the same to expel the gases therefrom and conducting said gases to the ammonia-tank, discharging the residuum, and adding` to the liquid in the system water sufficient to absorb bhe quantity ofgas collected from the reabsorbing liquid7 substantially as specified.

The method of producing anhydrous ammonia for motive or refrigerative purposes, which consists in empor-ating concentrated ammonia, separating the weaker solution re sulting from Said evaporation and conducting' il; to a receptacle, and continuously and direobly conducting any aqueous vapors arising therefrom to and re-evaporating the same with the concentrated ammonia bein g treated, substantially as speoiied.

In testimony whereof I affix my signature in presence ol' t-wo witnesses. PATRICK J. MCMAHON. `Wi messes: u

J. W. DAVIS', E. C. KELLY. 

